1. Field of the Invention
The present invention generally relates to removing material, for example, by machining diverse objects, or by marking and inscribing objects such as gemstones, particularly diamonds, with indicia identifying the gemstones. The material removal is performed by ultrasonically vibrating a liquid mixture of abrasive particles through cutouts in a mask, the cutouts being arranged in a pattern corresponding to the identifying indicia, or in a machining pattern.
2. Description of the Related Art
Laser etching or inscribing of a diamond surface for the purpose of permanently identifying a diamond is well known. U.S. Pat. No. 4,392,476; U.S. Pat. No. 4,467,172; U.S. Pat. No. 5,753,887; U.S. Pat. No. 5,932,119; U.S. Pat. No. 5,149,938; U.S. Pat. No. 5,410,125; U.S. Pat. No. 5,573,684; U.S. Pat. No. 6,211,484 and application Ser. No. 09/785,631 filed Feb. 16, 2001, U.S. Pat. No. 6,483,073, are representative of the prior art of laser marking systems that employ lasers, beam delivery and imaging components, gemstone fixtures, servomotors, optical encoders, and programmed computers for controlling the marking procedure.
Such marking systems not only occupy a large volume of space to accommodate all of their various components, but also are costly to purchase and operate. As a result, such systems are typically installed at one or more authorized sites, such as a gemological laboratory or institute. Jewelers and like customers desiring gemstones to be marked send the gemstones to the site of the marking system, and wait for the marked gemstones to be returned.
Many jewelers dislike sending precious items out of their hands and, hence, out of their sight and control, but perhaps, more importantly, dislike having to wait for their return. Yet, the size and cost of laser marking systems dictate against the average small jeweler""s purchasing and installing such a system at the jeweler""s premises. Such systems also require skilled, trained personnel to operate the system. This requirement is typically difficult for the average jeweler to meet.
I previously proposed in U.S. patent application Ser. No. 09/858,846, filed May 16, 2001, a flame marking system and method in which a flammable substance filled cutouts in a tape, and was thereupon ignited to scorch a gemstone in a burn pattern corresponding to the cutouts and the indicia to be marked. This technique required close monitoring of the flame produced after ignition to avoid the risk of fire. I also earlier proposed in U.S. patent application Ser. No. 09/909,174, filed Jul. 19, 2001, a gemstone marking system and method in which a radiant energy source caused a fusible coating to be fused on and in the surface of a gemstone in a marking pattern. In one embodiment, the fusible coating filled cutouts in a stencil. The energy source was preferably a laser, but could have been a radio frequency or microwave source. In both of my earlier applications, the marking was achieved at a jeweler""s premises.
It is also known to drill or bore holes through or in objects by using a high energy laser, or by ultrasonic drilling especially with brittle objects. The size of the ultrasonic drill bit dictates the size of the hole and, hence, such techniques are unsuitable for complex machining patterns or indicia patterns.
One object of this invention is to enable gemstones to be marked with identifying indicia without using large sized, costly laser or flame marking systems.
Another object of this invention is to reduce the skill level required for personnel to mark gemstones.
Still another object of this invention is to enable gemstone marking on-site at a jeweler""s premises.
Yet another object of this invention is to increase the use of gemstone marking by making the procedure more available and affordable to jewelers.
A further object of this invention is to mark diverse objects, not necessarily a gemstone, in a safe, reliable and permanent manner.
An additional object of this invention is to machine diverse objects with complex machining patterns.
In keeping with the above objects and others which will become apparent hereinafter, one feature of the present invention resides, briefly stated, in a vibratory system and method in which an apertured mask is mounted on a surface of an object from which material is to be removed. The mask has cutouts arranged in a pattern. A mixture of a liquid, preferably water, and abrasive particles, such as aluminum oxide, silicon carbide, diamond grit, or mixtures of these and/or other particles, is applied over the mask and fills the cutouts. A vibrator, preferably an ultrasonic piezoelectric transducer, agitates the mixture and propels the abrasive particles through the cutouts against the surface of the object in the pattern corresponding to the cutouts.
In one preferred application, the object is a gemstone, for example, a diamond, and it is desired to mark a surface, such as a table or girdle of the diamond, with identifying indicia. In this application, the pattern of the cutouts in the mask is configured to correspond with the indicia. The marking can be performed at a jeweler""s premises. No costly and large-sized machines for directly marking the diamond with a laser beam need be purchased or operated. No flames need be monitored. No costly radiant energy sources are used to fuse coatings at elevated temperatures.
In another application, the pattern of the cutouts is arranged in a machining pattern for objects to be machined. Such objects may include, by way of non-limiting example, microfluidic devices, DNA microarrays (DNA chips), microelectromechanical (MEM) devices, semiconductor wafers, lenses, substrates and, in general, any object to be drilled, cut, shaped or otherwise worked by material removal.